Ultrathin WO3 Nanosheets Converted from Metallic WS2 Sheets by Spontaneous Formation and Deposition of PdO Nanoclusters for Visible Light-driven C-C Coupling Reactions

It is not facile to obtain ultrathin two-dimensional (2D) WO3 nanosheets through the exfoliation of their bulk counterpart in solution due to strong covalent interaction between interlayers. In addition, they require additional functionalization with co-catalysts to expand their applicability in photocatalytic organic reactions owing to their insufficient conduction band edge position. Here, we report a chemical approach for the simultaneous production and functionalization of ultrathin 2D WO3 nanosheets through the direct conversion of metallic WS2 nanosheets, accomplished by the spontaneous formation and deposition of PdO nanoclusters on the nanosheet surface in H2O. When chemically exfoliated metallic WS2 nanosheets were simply mixed with K2PdCl4 in H2O under mild conditions (50 °C, 1 h), they were converted to semiconducting WO3 nanosheets on which PdO nanoclusters of a uniform size (~3 nm) were spontaneously formed, leading to the production of PdO-functionalized ultrathin WO3 (PdO@WO3) nanohybrids. ...